2025-11-05 17:04:23 -03:00

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# iq
> Info/Query, or IQ, is a "request-response" mechanism, similar in some ways to the Hypertext Transfer Protocol [HTTP]. The semantics of IQ enable an entity to make a request of, and receive a response from, another entity.
[XMPP Core: IQ Semantics](https://xmpp.org/rfcs/rfc6120.html#stanzas-semantics-iq)
Included in `@xmpp/client` and `@xmpp/component`.
## Caller
Implements the caller side of iq semantics.
```js
import { client } from "@xmpp/client"; // or component
const xmpp = client(...);
const {iqCaller} = xmpp;
```
### request
Sends an iq and returns a promise.
- Resolves with the response when it is received.
- Rejects with `StanzaError` when an error is received
- Rejects with `TimeoutError` if a reply wasn't received within the specified or default timeout
- Rejects with `Error` for anything else
* The request `id` attribute is optional and will be added if omitted.
* The request `to` attribute is optional and will default to the server.
```js
const response = await iqCaller.request(
xml("iq", { type: "get" }, xml("foo", "foo:bar")),
30 * 1000, // 30 seconds timeout - default
);
const foo = response.getChild("foo", "foo:bar");
console.log(foo);
```
### get
A convenient method to send a `get` request. Behaves like [request](#request) but accepts/returns a child element instead of an `iq`.
```js
const foo = await iqCaller.get(
xml("foo", "foo:bar"),
to, // "to" attribute, optional
timeout, // 30 seconds timeout - default
);
console.log(foo);
```
### set
A convenient method to send a `set` request. Behaves like [request](#request) but accepts/returns a child element instead of an `iq`.
```js
const foo = await iqCaller.set(
xml("foo", "foo:bar"),
to, // "to" attribute, optional
timeout, // 30 seconds timeout - default
);
console.log(foo);
```
## Callee
Implements the callee side of iq semantics.
You can think of this as http routing except there are only 2 methods; `get` and `set` and you would pass a namespace and a tag name instead of an url. The return value of the handler will be the child element of the response sent to the caller.
```js
import { client } from "@xmpp/client"; // or component
const xmpp = client(...);
const {iqCallee} = xmpp;
```
## get
Add a `get` handler.
```js
iqCallee.get("foo:bar", "foo", (ctx) => {
return xml("foo", { xmlns: "foo:bar" });
});
```
## set
Add a `set` handler.
```js
iqCallee.set("foo:bar", "foo", (ctx) => {
return xml("foo", { xmlns: "foo:bar" });
});
```
## References
[RFC 6120 IQ Semantics](https://xmpp.org/rfcs/rfc6120.html#stanzas-semantics-iq)